The present invention is directed to a corrosion resistant foundation for use in preparing a machine foundation, such as a foundation for a pump or the like, or for repairing an existing machine foundation.
Machines, such as pumps and other types of equipment, are usually bolted to concrete foundations so as to secure the pump or equipment in place. Concrete foundations may be coated with a comparatively thin (about 1/8 inch to about 1/4 inch) corrosion resistant polymer coating, which is relatively fragile and difficult, costly and time consuming to install. The concrete in the foundation, over time, may be attacked by the materials handled by the machine if the media involved is an aggressive chemical, such as by the liquids being pumped, or by the oils or greases that are used to lubricate the machines. Such attacks destroy the structural integrity of the machine foundation, and the loss of structural integrity allows the machine to vibrate, serving to further the destruction of the foundation and premature failure of the machine and or machine components. Still further, the machine foundations may also be subject to attack by chemicals from other nearby machines as those liquids may accumulate on the concrete floor to which the machine foundations are bonded or on which such foundations are situated. Concrete has limited chemical resistance and is subject to attack by a variety of chemicals. For instance, acids which react with the cement in the concrete and cause a breakdown of the integrity of the material.
An object of the invention is either to replace the concrete foundation with a corrosion resistant foundation, which is non-reactive, or to repair the remaining concrete portion of the foundation in such manner that only the corrosion resistant material will be exposed to such liquids, water, lubricating materials and the like, with the cementitious material involved in the construction of the foundation being encased within the corrosion resistant material.
By the use of the term "cementitious," it is meant generally the use of minerals that react with water and bond together to produce a hardened material that has rock-like properties. Portland type cements, for example, may be used to provide the aforementioned "minerals." These materials are also generally less expensive than corrosion resistant materials, and since the cementitious materials will not be exposed to corrosive influences, due to the manner in which the corrosion resistant machine foundation of the invention is constructed, there would be little purpose served in using more expensive materials to construct the bulk of the foundation. Also, the advantage of using cementitious materials enables repairs to be made in areas where water already exists, with that water participating in the curing or installation. This is not to say, however, that no other materials may be used, if one wanted to use same.
Other examples of cementitious materials suitable for use in the disclosed invention may be Speed Crete.RTM. 2028, as produced by Tamms Industries of Kirkland, Ill. This product is a proprietary formulation of blended Portland cements, finely processed selected aggregates, and specific chemical additives, is cement based, is rapid setting, and it achieves compressive strength of about 3600 psi (pounds per square inch) within one hour at 75 degrees Fahrenheit. Another suitable material is Five Star Structural Concrete.RTM., as produced by Five Star Products, Inc. of Fairfield, Conn. This material develops a bond strength of about 2000 psi (pounds per square inch) in about one day; provides optimum dimensional stability, meaning that the material will not pull away from the existing concrete; and it forms an integral bond to existing concrete.
The aforementioned corrosion resistant material will also not react with the fluids or liquids being handled by the machine, or by any lubricating materials used in connection with the machine. Such corrosion resistant material further will not be absorbent to such liquids or lubricants or greases. The corrosion resistant material making up the exposed surfaces of the machine will enable personnel to easily clean and maintain the foundation. Any leakage of corrosive materials being pumped, or if caustic or otherwise aggressive cleaning materials are used, these will also generally not be destructive of the integrity of the machine foundation. The end result of the use of corrosion resistant material will mean that the machine foundation will have a significantly longer life than a machine foundation, for example, constructed solely of cementitious materials or a coated-in-place foundation.
A further advantage to use of a corrosion resistant material for a machine foundation is that in an industrial setup, which is usually the case with such machine foundations, any breakdown of the integrity of a machine foundation, means lost production time until that foundation can be repaired or replaced and the pump or machine placed back into operation.
Such breakdown of the foundation, can also cause damage to seals in a pump, for instance, where the length and weight of the pump are such that the pump is no longer being supported on a level surface and thus being more susceptible to vibration.
A further object of the invention is to employ cementitious materials for the bulk of the machine foundation in such manner that it will not be exposed to liquids, lubricating materials, and the like, as previously mentioned, while the corrosion resistant material, which is generally much more expensive, will be employed on the exterior surfaces of the machine foundation. Further, the corrosion resistant material will be applied to such extent and in such thicknesses that any vibrations caused by the machine or any exterior abuse such as by impact from dropped tools, forklifts and the like will not cause any breakdown of the corrosion resistant materials.
Examples of suitable corrosion resistant materials that may be used in the construction of the corrosion resistant machine foundation of this invention include, for instance, Blome Number 35, a two component, silica filled resin bonded polymer concrete, produced by Blome Cements Company of O'Fallon, Mo. This material has resistance to a broad range of chemicals including most non-oxidizing acids and alkalis, solvents, water and weather. At 75 degrees Fahrenheit, this material will cure solid in about ten to about twelve hours. Another suitable Blome material that may be used is Blome Number 85, a non-shrink epoxy polymer grout having good resistance to a wide range of chemicals, oils and solvents. Still another Blome material: Blome Number 95, a three component, silica filled novalac epoxy polymer concrete, which exhibits excellent resistance to 98% sulfuric acid, concentrated hydrochloric acid and 50% sodium hydroxide. A further Blome material: Blome Number VE300, a three component, silica filled vinyl ester resin polymer grout, which is suitable for certain high temperature applications; strong oxidizing acids, such as nitric and chromic; and acid bleach or acid solvent solutions.
The use of corrosion resistant materials for the construction or repair of a machine foundation is known in the art. For instance, the Welch et al patents, U.S. Pat. No. 5,165,651 (1992) and U.S. Pat. No. 5,437,430 (1995), disclose a machine foundation and methods for preparing or repairing a machine foundation, which includes the use of aggregate filled thermosetting resin or a thermoplastic resin, which are corrosion and chemical resistant materials free from fluid attack. Welch et al indicate that the preferred form of the invention is a hollow form that has vertical walls and a single top horizontal wall, which has openings in the top through which fortifying materials such as epoxy based polymer concretes can be poured to fill the form. The hollow form used for such construction cannot be formed on the work site, but rather has to be manufactured. This means, of course, that measurements must be made at the work site of the damaged foundation that requires repair or a measurement made of the equipment to be supported by a foundation, and then this information is communicated to the manufacturing plant where the hollow form is then custom made to order. This takes time, and it means that the machine or equipment that is to be supported by the hollow form is shutdown and is, therefore, non-productive. An object of the present invention is to employ precast vertical panels made of an aggregate filled thermosetting resin that may be cut to size at the work site, the construction or repair taking place on the work site immediately, and restoration of the operation of the pump or machine taking place in about two to three days from the time measurements are taken. The use of precast vertical panels are easier and less expensive to manufacture. Such use also saves the costs of labor and materials involved in the old method of constructing wood or plywood forms that must be removed after a foundation has been poured and cured. The precast vertical panels of the invention, therefore, not only serve as a form for the foundation, but also remain permanently in place as part of the foundation. Further, the horizontal surface of the machine foundation of the present invention is formed as part of the pour of the corrosion resistant material.
The material used in forming vertically extending panels of aggregate filled thermosetting resin may be the same material employed in forming the pour of corrosion resistant materials, as referred to herein. For instance, the material employed includes selected aggregates bonded together with a thermoset plastic binder. These liquid thermoset resins require suitable curing agents to convert them from their liquid form into a fully cross-linked plastic, which then bonds completely with the aggregate. Typically, silica and quartz are the best fillers for use in polymer concrete or grout. The size of the aggregate also has an impact on the physical properties, and, in turn, the overall quality of the resulting polymer concrete. This latter aspect, however, is within the skill of the art and is well-known.
The use by Welch et al of thermoplastic resin in panels requires skill in welding the panels together. Usually, welding of thermoplastic panels also has to take place at the manufacturing plant because often personnel skilled in such welding and the equipment employed for such are not usually available at the work site. The invention disclosed herein, as previously mentioned, uses precast aggregate filled thermosetting panels, which may be cut to size at the work site.
In the FIG. 5 embodiment of each Welch et al patent, the hollow form is made from two forms, each form having a side vertical wall and an end vertical wall made of either an aggregate filled thermosetting resin or a thermoplastic resin, joined together to surround an existing degraded machine foundation. Each form has two tubular members formed on its end wall through which pins are inserted to hold the two forms together. Then a sealing material, such as an epoxy resin or other suitable adhesive for the aggregate filled thermosetting resin or the thermoplastic resin is applied along the connecting edges of the end walls of the forms where the forms are joined by the pins inserted through the tubular members. Although it is indicated that this embodiment may be constructed in the field, the forms and their tubular members still have to be made to the appropriate size at the manufacturing plant. After the two forms are connected together around the foundation to be repaired and appropriately sealed, the hollow form is filled with a fortifying material, such as a polymer concrete that is fast setting with very little shrinkage upon setting, substantially to the top of the form. The fortifying material is allowed to set, and thereafter the hollow form is filled with a layer of the same material used in making the two forms.
In the present invention, and as previously mentioned, the bulk of the machine foundation is comprised of a less expensive cementitious material than the corrosion resistant material. Also, to ensure that the joints where the intersections of the edges of the different panels come together to form the hollow form, a barrier is Formed interiorly of the hollow form across the resulting corners to create vertically extending channels. The resulting area or channel within each of the barriers is then filled with corrosion resistant material, which bonds well to the interior corners formed by the intersecting panels, and provides not only well-sealed interior corners, wherever a panel has intersected with an adjacent panel, but also provides a strong reinforced corner. The end result of this construction is to produce in a relatively short period of time an effective but less expensive machine foundation, which is not only resistant to any corrosion effect, but it is also resistant against any vibrations of the pump or equipment installed on the machine foundation.